While it is known that children of schizophrenia parents perform more poorly on tests of cognitive functioning than children of normal parents, less certain is the degree to which such deficits predict schizophrenia outcome, whether cognitive functioning deteriorates during childhood in preschizophrenia individuals, and whether nongenetic etiologic factors (such as obstetric complications) contribute to these deficits. In the present study, 72 patients with schizophrenia or schizoaffective disorder, 63 of their siblings not diagnosed with schizophrenia, and 7,941 controls with no diagnosis were ascertained from a birth cohort whose members had been evaluated with standardized tests of cognitive functioning at 4 and 7 years of age. Adult psychiatric morbidity was ascertained via a longitudinal treatment data base indexing regional public health service utilization, and diagnoses were made by review of all pertinent medical records according to DSAf-TV criteria. Both the patients with schizophrenia and their unaffected siblings performed significantly worse than the nonpsychiatric controls (but did not differ from each other) on verbal and nonverbal cognitive tests at 4 and 7 years of age. Preschizophrenia cases and their siblings were increasingly overrepresented across decreasing quartiles of the performance distributions. There was not significant intra-individual decline, and there were no significant relationships between obstetric complications and test performance among the preschizophrenia subjects. These results suggest that during the period from age 4 to age 7 years, premorbid cognitive dysfunction in schizophrenia represents a relatively stable indicator of vulnerability deriving from primarily genetic (and/or shared environmental) etiologic influences. Findings of cytoarchitectural and morphologic brain changes consistent with a prenatal and perinatal origin have led to the notion that neurodevelopmental disturbances contribute to the etiology of at least some cases of adult schizophrenia (Kovelman and Scheibel 1984;Jakob and Beckmann 1986;Weintraub 1987;Arnold et al. 1991;Akbarian et al. 1993;Cannon et al. 1993). However, the etiologic correlates of these disturbances and the proportion of the population with schizophrenia that they characterize remain to be determined (Lewis and Murray 1987;Cannon and Mednick 1991). Prospective examination of cognitive functioning in individuals who develop schizophrenia as adults provides an indirect means to address these questions. Longitudinal "high-risk" studies have consistently reported that children of patients with schizophrenia perform more poorly on neuropsychological tests than children of other people (Mednick and Schulsinger 1968;Landau et al. 1972;Asarnow et al. 1978;Rutschmann et al. 1980;Harvey et al. 1981;Winters et al. 1981;Worland et al. 1982;Driscoll 1984;Lifshitz et al. 1985;Sohlberg 1985;Hallett et al. 1986;Fish 1987;Goodman 1987;Sameroff et al. 1987;Weintraub 1987;Erlenmeyer-Kimling et al. 1989;Schreiber et al. 1992;Marcus et al. 1993...

Background: Cortical gray matter reductions and cerebrospinal fluid (CSF) increases are robust correlates of schizophrenia, but their relationships to obstetric and other etiologic risk factors remain to be established.

In this study, we examined whether fetal hypoxia and other obstetric complications (OCs) are related to risk for adult schizophrenia; whether such effects are specific to cases with an early age at onset; and whether the obstetric influences depend on, covary with, or are independent of familial risk. Subjects were 72 patients with schizophrenia or schizoaffective disorder; 63 of their siblings not diagnosed with schizophrenia; and 7,941 nonpsychiatric controls, whose gestations and births were monitored prospectively with standard research protocols as part of the National Collaborative Perinatal Project Adult psychiatric morbidity was ascertained via a longitudinal treatment data base indexing regional public health service utilization, and diagnoses were made by review of all pertinent medical records according to DSM-IV criteria. We found that the odds of schizophrenia increased linearly with increasing number of hypoxia-assodated OCs and that this effect was specific to cases with an early age at onset/first treatment contact There were no relationships between schizophrenia and birth weight or other (prenatal/nonhypoxic) OCs. Siblings of patients with schizophrenia were no more likely to have suffered hypoxia-associated OCs than were nonpsychiatric cohort controls. Because the majority of individuals exposed to fetal hypoxia did not develop schizophrenia, such factors likely are incapable of causing schizophrenia on their own. Together, these findings suggest that hypoxia acts additively or interactively with genetic factors in influencing liability to schizophrenia. We propose a model In which the neurotoxic effects of fetal hypoxia may lead to an earlier onset of psychosis because of premature pruning of cortical synapses.

As a step toward addressing limitations in the current psychiatric diagnostic system, the NIMH recently developed the Research Domain Criteria (RDoC) to stimulate integrative research—spanning self-report, behavior, neural circuitry, and molecular/genetic mechanisms—on core psychological processes implicated in mental illness. Here, we use the RDoC conceptualization to review research on threat responses, reward processing, and their interaction. The first section of the manuscript highlights the pivotal role of exaggerated threat responses—mediated by circuits connecting the frontal cortex, amygdala, and midbrain—in anxiety, and reviews data indicating that genotypic variation in the serotonin system is associated with hyperactivity in this circuitry, which elevates the risk for anxiety and mood disorders. In the second section, we describe mounting evidence linking anhedonic behavior to deficits in psychological functions that rely heavily on dopamine signaling, especially cost/benefit decision-making and reward learning. The third section covers recent studies that document negative effects of acute threats and chronic stress on reward responses in humans. The mechanisms underlying such effects are unclear, but new optogenetic data in rodents indicate that GABAergic inhibition of midbrain dopamine neurons, driven by activation of the habenula, may play a fundamental role in stress-induced anhedonia. In addition to its basic scientific value, a better understanding of interactions between the neural systems that mediate threat and reward responses may offer relief from the burdensome condition of anxious depression.

Background The brain undergoes major remodeling during adolescence, resulting in improved cognitive control and decision-making, and reduced impulsivity, components of behavior mediated in part by the maturing frontal lobe. Gamma-amino butyric acid (GABA), the main inhibitory neurotransmitter system, also matures during adolescence, with frontal lobe GABA receptors reaching adult levels late in adolescence. Thus, the objective of this study was to characterize in vivo developmental differences in brain GABA levels. Methods Proton magnetic resonance spectroscopy (MRS) was employed at 4 Tesla to acquire metabolite data from the anterior cingulate cortex (ACC) and the parieto-occipital (POC) cortex in adolescents (n=30) and emerging adults (n=20). Results ACC GABA/Cr levels were significantly lower in adolescents relative to emerging adults, whereas no age differences were observed in the POC. Lower ACC GABA/Cr levels were significantly associated with greater impulsivity and worse response inhibition, with relationships being most pronounced for ACC GABA/Cr and No-Go response inhibition in adolescent males. Conclusions These data provide the first human developmental in vivo evidence confirming frontal lobe GABA maturation, which was linked to impulsiveness and cognitive control. These findings suggest that reduced GABA may be an important neurobiological mechanism in the immature adolescent brain, contributing to the reduced, yet rapidly developing, ability to inhibit risky behaviors and to make decisions, which could compromise adolescent health and safety.

No abstract

No abstract

These findings suggest that in patients with schizophrenia spectrum disorders, hippocampal volume is influenced in part by schizophrenia susceptibility genes and an interaction of these genes with fetal hypoxia. They further suggest that hippocampal volume in schizophrenia or schizoaffective disorder may be linked to time of disease onset.